Senate Minority Leader Mitch McConnell isn’t willing to wager on whether Republicans will take control of the chamber after this fall’s elections. But he knows the battle for 51 seats over the next five months is going to be ugly.

“I’m not going to make a prediction other than this: I think the Senate is going to be close, one way or the other,” he said. “It’s going to be an eye-gouging, shin-kicking contest all the way to the finish line.”

In an interview with Roll Call last week in his Capitol office, the man who could be Majority Leader in the 113th Congress outlined the races pivotal to control and discussed candidate recruitment, the role of outside forces on GOP primaries and the effect of White House nominee Mitt Romney on Senate races.

The Senator said he sees three different levels of competitiveness in 2012 races where his party could add seats. The races that represent the best chance for GOP pickups are the open seat in North Dakota, Sen. Jon Tester’s (D) very competitive race in Montana, the open seat in Nebraska, Sen. Claire McCaskill’s (D) uphill re-election bid in Missouri and the marquee matchup between former Govs. Tim Kaine (D) and George Allen (R) in Virginia.

McConnell’s “tier two” races include Sen. Sherrod Brown’s re-election effort in Ohio and the open seats in Wisconsin, New Mexico and Hawaii.

Then there are states less likely to lead to GOP pickups this cycle.

“Maine, Pennsylvania, Florida are examples of ones you take a look at later,” said McConnell, who was chairman of the National Republican Senatorial Committee in the 1998 and 2000 cycles. “Sorta see what develops.”

The party must also hold its own seats, particularly in Massachusetts, Nevada and Maine. Asked how much of a blow the retirement of Republican Sen. Olympia Snowe (Maine) is to GOP efforts to take the Senate, McConnell said it was “not helpful.”

It didn’t sound as if he sees Maine being a state that might come into serious play.

“We think it’s certainly a lean-blue state. Whether it’s a completely deep blue state, I don’t know,” the Senator said, noting there are a large number of independent voters there. He said the GOP would assess the race after the June 12 primary.

As for frontrunner Angus King (I), the state’s former governor who has not said with whom he would caucus should he be elected to the Senate, McConnell all but wrote him off.

“He is kind of the de facto Democratic candidate,” the Minority Leader said. “It looks to me like they’ve adopted him.”

In the 30-minute interview, McConnell had little venom for Democrats and, in fact, offered the opposing party praise.

“I’ll say this for our competition: They’ve done a good job on candidate recruitment, they’ve done a good job on fundraising,” he said. “You know, they’re certainly not going to roll over.”

He also noted GOP recruiting successes in Rep. Rick Berg in North Dakota, Rep. Denny Rehberg in Montana, former Rep. Heather Wilson in New Mexico and former Gov. Linda Lingle in Hawaii. He had particular praise for Lingle, who put the heavily Democratic state in play.

It’s one of two very competitive races being waged in states President Barack Obama is expected to carry by a wide margin. The other is the white-hot race between Sen. Scott Brown (R) and Harvard professor Elizabeth Warren (D) in Massachusetts.

McConnell cautioned not to overestimate the power of the top of the ticket in other, more competitive states.

“I’m not saying there’s no impact at all from the presidential race, but I’m not one of those who believes that the fate of the Senate is inexorably intertwined,” he said.

Still, his prospects of becoming Majority Leader next year are, at the least, tied somewhat to the success of Romney. A victory by the former Massachusetts governor means the GOP can secure the majority by netting just three seats, rather than four.

The Obama campaign’s wide network of field offices in battleground states such as Nevada and Virginia will no doubt benefit the Democratic Senate nominees in those states. Romney’s ability to match those efforts, and perhaps dangle coattails down-ticket could mean the difference between another two years in the Senate minority and control over the chamber for the first time since 2006.

Romney and McConnell met in Washington, D.C., last week, and the Senator said the two have established a “good working relationship.”

“We want to basically stay in coordination as best we can, because if we’re all fortunate enough to be given the responsibility of governing next year, we want to be ready to go.”

McConnell, now serving his 27th year in the Senate, has faced hurdles in his drive to be Majority Leader — and not all from Democrats.

Republican primaries continue to illustrate a divide among forces within the GOP. Groups such as the powerful anti-tax Club for Growth and people such as Sen. Jim DeMint (R-S.C.) and former Alaska Gov. Sarah Palin have weighed in on intraparty races in states such as Texas, which held its primary Tuesday, Indiana and Nebraska — all races Republicans are favored to win.

Money flowed into Indiana in an effort to defeat longtime Sen. Dick Lugar, whose primary loss to state Treasurer Richard Mourdock could force the national party to expend valuable resources to lock up the seat. In Texas, Lt. Gov. David Dewhurst was forced into a runoff with former state Solicitor General Ted Cruz, a tea party favorite.

McConnell said Senators and others have every right to get involved in primaries, something the national party has carefully chosen not to do this cycle. But he has only one goal.

“I think we all benefit on our side from having more of us,” he said. “Only the people who win elections get to make policy. So I’m obviously more drawn to and more appreciative of people who work smart and whose goal is to defeat Democrats. But everybody is free to operate any way they choose to, both within and without the Senate.”

Finally, McConnell said, if Republicans take the Senate and the White House, they would have to be sure not to over-read their mandate.

“Governing is hard. The things that we need to do to straighten this country out are not going to be popular,” he said. “I think you need to start out with humility, but with determination to deal with the truly big problems in the country.”